Today, users have higher demand requirements for display devices. To satisfy such requirements, some flat panel display devices have been rapidly developed in recent years, such as liquid crystal display (LCD) device, Plasma Display Panel (PDP), and Organic Light-Emitting Diode (OLED) display device. In flat panel display devices, LCD devices are gradually replacing cold cathode display devices due to low weight, small volume, and low energy consumption.
An initial LCD mode has a low contrast ratio and a poor viewing angle, such as a twisted nematic (TN) display and a super twisted nematic (STN) display. With the growth of living standards, users demand improved display devices. Thus, some LCD modes having a wide visual angle have developed rapidly in recent years, such as an in-plan switching (IPS) display and a vertical alignment (VA) display.
For the VA display, the LCD device includes a first substrate, a second substrate, and negative liquid crystal (LC) molecules between the first substrate and the second substrate. Transparent conducting layers (indium tin oxide: ITO) are layered on insides of the first substrate and the second substrate, which forms a vertical electric field. The negative LC molecules are embedded between two transparent conducting layers. Dielectric constant of a long axis of the negative LC molecule is less than dielectric constant of a secondary axis of the negative LC molecule, where the secondary axis of the negative LC molecule is perpendicular to the long axis of the negative LC molecule. When the LC molecule is not affected by the vertical electric field, the LC molecule is perpendicular to surfaces of the first and second substrates. When the LC molecule is affected by the vertical electric field, the LC molecule is oriented toward a designated direction and finally arrays along a direction perpendicular to the vertical electric field because of small dielectric constant of the long axis of the LC molecule. Compared with the IPS display mode, the VA display mode has no friction process in a manufacturing process, which increases advantages of manufacturing the LCD device on a large-scale.
The initial VA mode is a multi-domain vertical alignment (MVA) mode, the MVA mode achieves a multi-domain display (generally, four domains) through forming a rib having a predetermined shape on a color film substrate, and the MVA mode improves the viewing angle of the VA mode. However, some defects are generated, the LC molecules in a determined range surrounding the rib have a poor vertical orientation due to the rib on the color film substrate, thus, light leak exists, which affects the contrast ratio of the MVA mode.
With the development of the technology, the MVA technology is improved, and a patterned vertical alignment (PVA) mode is generated. In the PVA mode, a corresponding ITO pattern is formed on a transparent electrode (ITO) of the color film substrate, and the rib is not formed. The pattern may be an ITO slit, and a width of the ITO slit is usually between 8-15 um. The PVA technology does not need to form the rib, and sharply reduces the light leak.
However, other defects are generated in the MAV mode and the PVA mode, transmittances of the rib of the MAV mode and the ITO slit of the PVA mode are far less than transmittance of a normal pixel region, which affects an entire transmittance of the device.
In view of the above-described problems, a new VA mode is generated, and the rib and the ITO slit are not formed on the color film substrate 21 of the new VA mode, which reduces manufacturing cost of the color film and improves the entire transmittance of the device. As shown in FIG. 1A to FIG. 1C, the new VA mode is named as a polymer sustained vertical alignment (PSVA) mode. The color film of the PSVA mode is not only different from the MVA mode and the PVA mode, but also the LC molecule and the pattern of the transparent electrode of the substrate of the PSVA are different from the MVA mode and the PVA mode. In the PSVA mode, a reactive monomer 40 is added into original negative LC molecules 30, and the reactive monomers 40 perform a reaction according to a determined law under an external influence. The width of the transparent electrode 10 and transparent electrode slit 11 are small on transparent electrode pattern of the array substrate 22.
In a manufacturing process of an LCD panel, some LC molecules are remained in an LC bottle. The residual LC molecules should be recycled, purified, and reused, which reduces manufacturing cost. However, the reactive monomer having high-activity is directly added into the LC molecules of the PSVA mode, concentration of the reactive monomer is not easy to manage and the reactive monomer can perform the reaction, thus the LC molecule of the PSVA mode cannot be purified and reused.